[ruby/json] Stop caching the generator state pointer

Fix: https://github.com/ruby/json/issues/790

If we end up calling something that spills the state
on the heap, the pointer we received is outdated and
may be out of sync.

https://github.com/ruby/json/commit/2ffa4ea46b
This commit is contained in:
Jean Boussier 2025-04-25 07:35:05 +02:00
parent 18dac125cb
commit 8fe3fb5d5a
2 changed files with 114 additions and 89 deletions

View File

@ -45,7 +45,7 @@ static VALUE sym_indent, sym_space, sym_space_before, sym_object_nl, sym_array_n
struct generate_json_data; struct generate_json_data;
typedef void (*generator_func)(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); typedef void (*generator_func)(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
struct generate_json_data { struct generate_json_data {
FBuffer *buffer; FBuffer *buffer;
@ -57,20 +57,20 @@ struct generate_json_data {
static VALUE cState_from_state_s(VALUE self, VALUE opts); static VALUE cState_from_state_s(VALUE self, VALUE opts);
static VALUE cState_partial_generate(VALUE self, VALUE obj, generator_func, VALUE io); static VALUE cState_partial_generate(VALUE self, VALUE obj, generator_func, VALUE io);
static void generate_json(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_object(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_object(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_array(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_array(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_string(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_string(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_null(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_null(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_false(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_false(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_true(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_true(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
#ifdef RUBY_INTEGER_UNIFICATION #ifdef RUBY_INTEGER_UNIFICATION
static void generate_json_integer(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_integer(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
#endif #endif
static void generate_json_fixnum(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_fixnum(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_bignum(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_bignum(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_float(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_float(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static void generate_json_fragment(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj); static void generate_json_fragment(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
static int usascii_encindex, utf8_encindex, binary_encindex; static int usascii_encindex, utf8_encindex, binary_encindex;
@ -802,12 +802,12 @@ json_object_i(VALUE key, VALUE val, VALUE _arg)
int j; int j;
if (arg->iter > 0) fbuffer_append_char(buffer, ','); if (arg->iter > 0) fbuffer_append_char(buffer, ',');
if (RB_UNLIKELY(state->object_nl)) { if (RB_UNLIKELY(data->state->object_nl)) {
fbuffer_append_str(buffer, state->object_nl); fbuffer_append_str(buffer, data->state->object_nl);
} }
if (RB_UNLIKELY(state->indent)) { if (RB_UNLIKELY(data->state->indent)) {
for (j = 0; j < depth; j++) { for (j = 0; j < depth; j++) {
fbuffer_append_str(buffer, state->indent); fbuffer_append_str(buffer, data->state->indent);
} }
} }
@ -829,21 +829,22 @@ json_object_i(VALUE key, VALUE val, VALUE _arg)
} }
if (RB_LIKELY(RBASIC_CLASS(key_to_s) == rb_cString)) { if (RB_LIKELY(RBASIC_CLASS(key_to_s) == rb_cString)) {
generate_json_string(buffer, data, state, key_to_s); generate_json_string(buffer, data, key_to_s);
} else { } else {
generate_json(buffer, data, state, key_to_s); generate_json(buffer, data, key_to_s);
} }
if (RB_UNLIKELY(state->space_before)) fbuffer_append_str(buffer, state->space_before); if (RB_UNLIKELY(state->space_before)) fbuffer_append_str(buffer, data->state->space_before);
fbuffer_append_char(buffer, ':'); fbuffer_append_char(buffer, ':');
if (RB_UNLIKELY(state->space)) fbuffer_append_str(buffer, state->space); if (RB_UNLIKELY(state->space)) fbuffer_append_str(buffer, data->state->space);
generate_json(buffer, data, state, val); generate_json(buffer, data, val);
arg->iter++; arg->iter++;
return ST_CONTINUE; return ST_CONTINUE;
} }
static inline long increase_depth(JSON_Generator_State *state) static inline long increase_depth(struct generate_json_data *data)
{ {
JSON_Generator_State *state = data->state;
long depth = ++state->depth; long depth = ++state->depth;
if (RB_UNLIKELY(depth > state->max_nesting && state->max_nesting)) { if (RB_UNLIKELY(depth > state->max_nesting && state->max_nesting)) {
rb_raise(eNestingError, "nesting of %ld is too deep", --state->depth); rb_raise(eNestingError, "nesting of %ld is too deep", --state->depth);
@ -851,14 +852,14 @@ static inline long increase_depth(JSON_Generator_State *state)
return depth; return depth;
} }
static void generate_json_object(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_object(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
int j; int j;
long depth = increase_depth(state); long depth = increase_depth(data);
if (RHASH_SIZE(obj) == 0) { if (RHASH_SIZE(obj) == 0) {
fbuffer_append(buffer, "{}", 2); fbuffer_append(buffer, "{}", 2);
--state->depth; --data->state->depth;
return; return;
} }
@ -870,49 +871,49 @@ static void generate_json_object(FBuffer *buffer, struct generate_json_data *dat
}; };
rb_hash_foreach(obj, json_object_i, (VALUE)&arg); rb_hash_foreach(obj, json_object_i, (VALUE)&arg);
depth = --state->depth; depth = --data->state->depth;
if (RB_UNLIKELY(state->object_nl)) { if (RB_UNLIKELY(data->state->object_nl)) {
fbuffer_append_str(buffer, state->object_nl); fbuffer_append_str(buffer, data->state->object_nl);
if (RB_UNLIKELY(state->indent)) { if (RB_UNLIKELY(data->state->indent)) {
for (j = 0; j < depth; j++) { for (j = 0; j < depth; j++) {
fbuffer_append_str(buffer, state->indent); fbuffer_append_str(buffer, data->state->indent);
} }
} }
} }
fbuffer_append_char(buffer, '}'); fbuffer_append_char(buffer, '}');
} }
static void generate_json_array(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_array(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
int i, j; int i, j;
long depth = increase_depth(state); long depth = increase_depth(data);
if (RARRAY_LEN(obj) == 0) { if (RARRAY_LEN(obj) == 0) {
fbuffer_append(buffer, "[]", 2); fbuffer_append(buffer, "[]", 2);
--state->depth; --data->state->depth;
return; return;
} }
fbuffer_append_char(buffer, '['); fbuffer_append_char(buffer, '[');
if (RB_UNLIKELY(state->array_nl)) fbuffer_append_str(buffer, state->array_nl); if (RB_UNLIKELY(data->state->array_nl)) fbuffer_append_str(buffer, data->state->array_nl);
for(i = 0; i < RARRAY_LEN(obj); i++) { for(i = 0; i < RARRAY_LEN(obj); i++) {
if (i > 0) { if (i > 0) {
fbuffer_append_char(buffer, ','); fbuffer_append_char(buffer, ',');
if (RB_UNLIKELY(state->array_nl)) fbuffer_append_str(buffer, state->array_nl); if (RB_UNLIKELY(data->state->array_nl)) fbuffer_append_str(buffer, data->state->array_nl);
} }
if (RB_UNLIKELY(state->indent)) { if (RB_UNLIKELY(data->state->indent)) {
for (j = 0; j < depth; j++) { for (j = 0; j < depth; j++) {
fbuffer_append_str(buffer, state->indent); fbuffer_append_str(buffer, data->state->indent);
} }
} }
generate_json(buffer, data, state, RARRAY_AREF(obj, i)); generate_json(buffer, data, RARRAY_AREF(obj, i));
} }
state->depth = --depth; data->state->depth = --depth;
if (RB_UNLIKELY(state->array_nl)) { if (RB_UNLIKELY(data->state->array_nl)) {
fbuffer_append_str(buffer, state->array_nl); fbuffer_append_str(buffer, data->state->array_nl);
if (RB_UNLIKELY(state->indent)) { if (RB_UNLIKELY(data->state->indent)) {
for (j = 0; j < depth; j++) { for (j = 0; j < depth; j++) {
fbuffer_append_str(buffer, state->indent); fbuffer_append_str(buffer, data->state->indent);
} }
} }
} }
@ -961,7 +962,7 @@ static inline VALUE ensure_valid_encoding(VALUE str)
return str; return str;
} }
static void generate_json_string(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_string(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
obj = ensure_valid_encoding(obj); obj = ensure_valid_encoding(obj);
@ -977,9 +978,9 @@ static void generate_json_string(FBuffer *buffer, struct generate_json_data *dat
switch(rb_enc_str_coderange(obj)) { switch(rb_enc_str_coderange(obj)) {
case ENC_CODERANGE_7BIT: case ENC_CODERANGE_7BIT:
case ENC_CODERANGE_VALID: case ENC_CODERANGE_VALID:
if (RB_UNLIKELY(state->ascii_only)) { if (RB_UNLIKELY(data->state->ascii_only)) {
convert_UTF8_to_ASCII_only_JSON(&search, state->script_safe ? script_safe_escape_table : ascii_only_escape_table); convert_UTF8_to_ASCII_only_JSON(&search, data->state->script_safe ? script_safe_escape_table : ascii_only_escape_table);
} else if (RB_UNLIKELY(state->script_safe)) { } else if (RB_UNLIKELY(data->state->script_safe)) {
convert_UTF8_to_script_safe_JSON(&search); convert_UTF8_to_script_safe_JSON(&search);
} else { } else {
convert_UTF8_to_JSON(&search); convert_UTF8_to_JSON(&search);
@ -992,7 +993,7 @@ static void generate_json_string(FBuffer *buffer, struct generate_json_data *dat
fbuffer_append_char(buffer, '"'); fbuffer_append_char(buffer, '"');
} }
static void generate_json_fallback(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_fallback(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
VALUE tmp; VALUE tmp;
if (rb_respond_to(obj, i_to_json)) { if (rb_respond_to(obj, i_to_json)) {
@ -1002,68 +1003,68 @@ static void generate_json_fallback(FBuffer *buffer, struct generate_json_data *d
} else { } else {
tmp = rb_funcall(obj, i_to_s, 0); tmp = rb_funcall(obj, i_to_s, 0);
Check_Type(tmp, T_STRING); Check_Type(tmp, T_STRING);
generate_json_string(buffer, data, state, tmp); generate_json_string(buffer, data, tmp);
} }
} }
static inline void generate_json_symbol(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static inline void generate_json_symbol(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
if (state->strict) { if (data->state->strict) {
generate_json_string(buffer, data, state, rb_sym2str(obj)); generate_json_string(buffer, data, rb_sym2str(obj));
} else { } else {
generate_json_fallback(buffer, data, state, obj); generate_json_fallback(buffer, data, obj);
} }
} }
static void generate_json_null(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_null(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
fbuffer_append(buffer, "null", 4); fbuffer_append(buffer, "null", 4);
} }
static void generate_json_false(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_false(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
fbuffer_append(buffer, "false", 5); fbuffer_append(buffer, "false", 5);
} }
static void generate_json_true(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_true(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
fbuffer_append(buffer, "true", 4); fbuffer_append(buffer, "true", 4);
} }
static void generate_json_fixnum(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_fixnum(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
fbuffer_append_long(buffer, FIX2LONG(obj)); fbuffer_append_long(buffer, FIX2LONG(obj));
} }
static void generate_json_bignum(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_bignum(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
VALUE tmp = rb_funcall(obj, i_to_s, 0); VALUE tmp = rb_funcall(obj, i_to_s, 0);
fbuffer_append_str(buffer, tmp); fbuffer_append_str(buffer, tmp);
} }
#ifdef RUBY_INTEGER_UNIFICATION #ifdef RUBY_INTEGER_UNIFICATION
static void generate_json_integer(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_integer(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
if (FIXNUM_P(obj)) if (FIXNUM_P(obj))
generate_json_fixnum(buffer, data, state, obj); generate_json_fixnum(buffer, data, obj);
else else
generate_json_bignum(buffer, data, state, obj); generate_json_bignum(buffer, data, obj);
} }
#endif #endif
static void generate_json_float(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_float(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
double value = RFLOAT_VALUE(obj); double value = RFLOAT_VALUE(obj);
char allow_nan = state->allow_nan; char allow_nan = data->state->allow_nan;
if (isinf(value) || isnan(value)) { if (isinf(value) || isnan(value)) {
/* for NaN and Infinity values we either raise an error or rely on Float#to_s. */ /* for NaN and Infinity values we either raise an error or rely on Float#to_s. */
if (!allow_nan) { if (!allow_nan) {
if (state->strict && state->as_json) { if (data->state->strict && data->state->as_json) {
VALUE casted_obj = rb_proc_call_with_block(state->as_json, 1, &obj, Qnil); VALUE casted_obj = rb_proc_call_with_block(data->state->as_json, 1, &obj, Qnil);
if (casted_obj != obj) { if (casted_obj != obj) {
increase_depth(state); increase_depth(data);
generate_json(buffer, data, state, casted_obj); generate_json(buffer, data, casted_obj);
state->depth--; data->state->depth--;
return; return;
} }
} }
@ -1089,30 +1090,30 @@ static void generate_json_float(FBuffer *buffer, struct generate_json_data *data
buffer->len += len; buffer->len += len;
} }
static void generate_json_fragment(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json_fragment(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
VALUE fragment = RSTRUCT_GET(obj, 0); VALUE fragment = RSTRUCT_GET(obj, 0);
Check_Type(fragment, T_STRING); Check_Type(fragment, T_STRING);
fbuffer_append_str(buffer, fragment); fbuffer_append_str(buffer, fragment);
} }
static void generate_json(FBuffer *buffer, struct generate_json_data *data, JSON_Generator_State *state, VALUE obj) static void generate_json(FBuffer *buffer, struct generate_json_data *data, VALUE obj)
{ {
bool as_json_called = false; bool as_json_called = false;
start: start:
if (obj == Qnil) { if (obj == Qnil) {
generate_json_null(buffer, data, state, obj); generate_json_null(buffer, data, obj);
} else if (obj == Qfalse) { } else if (obj == Qfalse) {
generate_json_false(buffer, data, state, obj); generate_json_false(buffer, data, obj);
} else if (obj == Qtrue) { } else if (obj == Qtrue) {
generate_json_true(buffer, data, state, obj); generate_json_true(buffer, data, obj);
} else if (RB_SPECIAL_CONST_P(obj)) { } else if (RB_SPECIAL_CONST_P(obj)) {
if (RB_FIXNUM_P(obj)) { if (RB_FIXNUM_P(obj)) {
generate_json_fixnum(buffer, data, state, obj); generate_json_fixnum(buffer, data, obj);
} else if (RB_FLONUM_P(obj)) { } else if (RB_FLONUM_P(obj)) {
generate_json_float(buffer, data, state, obj); generate_json_float(buffer, data, obj);
} else if (RB_STATIC_SYM_P(obj)) { } else if (RB_STATIC_SYM_P(obj)) {
generate_json_symbol(buffer, data, state, obj); generate_json_symbol(buffer, data, obj);
} else { } else {
goto general; goto general;
} }
@ -1120,43 +1121,43 @@ start:
VALUE klass = RBASIC_CLASS(obj); VALUE klass = RBASIC_CLASS(obj);
switch (RB_BUILTIN_TYPE(obj)) { switch (RB_BUILTIN_TYPE(obj)) {
case T_BIGNUM: case T_BIGNUM:
generate_json_bignum(buffer, data, state, obj); generate_json_bignum(buffer, data, obj);
break; break;
case T_HASH: case T_HASH:
if (klass != rb_cHash) goto general; if (klass != rb_cHash) goto general;
generate_json_object(buffer, data, state, obj); generate_json_object(buffer, data, obj);
break; break;
case T_ARRAY: case T_ARRAY:
if (klass != rb_cArray) goto general; if (klass != rb_cArray) goto general;
generate_json_array(buffer, data, state, obj); generate_json_array(buffer, data, obj);
break; break;
case T_STRING: case T_STRING:
if (klass != rb_cString) goto general; if (klass != rb_cString) goto general;
generate_json_string(buffer, data, state, obj); generate_json_string(buffer, data, obj);
break; break;
case T_SYMBOL: case T_SYMBOL:
generate_json_symbol(buffer, data, state, obj); generate_json_symbol(buffer, data, obj);
break; break;
case T_FLOAT: case T_FLOAT:
if (klass != rb_cFloat) goto general; if (klass != rb_cFloat) goto general;
generate_json_float(buffer, data, state, obj); generate_json_float(buffer, data, obj);
break; break;
case T_STRUCT: case T_STRUCT:
if (klass != cFragment) goto general; if (klass != cFragment) goto general;
generate_json_fragment(buffer, data, state, obj); generate_json_fragment(buffer, data, obj);
break; break;
default: default:
general: general:
if (state->strict) { if (data->state->strict) {
if (RTEST(state->as_json) && !as_json_called) { if (RTEST(data->state->as_json) && !as_json_called) {
obj = rb_proc_call_with_block(state->as_json, 1, &obj, Qnil); obj = rb_proc_call_with_block(data->state->as_json, 1, &obj, Qnil);
as_json_called = true; as_json_called = true;
goto start; goto start;
} else { } else {
raise_generator_error(obj, "%"PRIsVALUE" not allowed in JSON", CLASS_OF(obj)); raise_generator_error(obj, "%"PRIsVALUE" not allowed in JSON", CLASS_OF(obj));
} }
} else { } else {
generate_json_fallback(buffer, data, state, obj); generate_json_fallback(buffer, data, obj);
} }
} }
} }
@ -1166,7 +1167,7 @@ static VALUE generate_json_try(VALUE d)
{ {
struct generate_json_data *data = (struct generate_json_data *)d; struct generate_json_data *data = (struct generate_json_data *)d;
data->func(data->buffer, data, data->state, data->obj); data->func(data->buffer, data, data->obj);
return Qnil; return Qnil;
} }

View File

@ -91,6 +91,30 @@ class JSONCommonInterfaceTest < Test::Unit::TestCase
def test_pretty_generate def test_pretty_generate
assert_equal "[\n 1,\n 2,\n 3\n]", JSON.pretty_generate([ 1, 2, 3 ]) assert_equal "[\n 1,\n 2,\n 3\n]", JSON.pretty_generate([ 1, 2, 3 ])
assert_equal <<~JSON.strip, JSON.pretty_generate({ a: { b: "f"}, c: "d"})
{
"a": {
"b": "f"
},
"c": "d"
}
JSON
# Cause the state to be spilled on the heap.
o = Object.new
def o.to_s
"Object"
end
actual = JSON.pretty_generate({ a: { b: o}, c: "d", e: "f"})
assert_equal <<~JSON.strip, actual
{
"a": {
"b": "Object"
},
"c": "d",
"e": "f"
}
JSON
end end
def test_load def test_load